Underground transformer enclosure, and method of installing the same

ABSTRACT

The enclosure for buried transformers is formed of two separate fiberglass parts, namely a hole liner and a cover. The hole liner comprises two corresponding semicylindrical sections which are joined together and then mounted around the transformer, in vertical relationship. The cover comprises a top portion and a skirt portion, and includes depending conduits for convecting cooling air down to the bottom of the hole liner. The convected air then passes upwardly through a central opening in the top portion of the cover. In accordance with the method, earth is compacted around the hole liner, following which the cover is mounted in telescoped relationship around the upper region of the hole liner. The cover is supported on the compacted earth, not on the hole liner, which means that the cover position is readily adjusted in the event the grade changes.

United States Patent [191 Griffing 1 Apr. 17, 1973 UNDERGROUNDTRANSFORMER OTHER PUBLICATIONS x5 3 OF Stewart, W. A. Cooling ofDistribution Transformers in Vented Underground Vaults, IEEE Trans. Vol.[76] Inventor: Roy Griffing, 485 North State PAS-88, No. 6June 1969Highway, Lake Arrowhead, Calif. 92352 Primary Examiner-Bernard A.Gilheany [22] Filed: AP 17 1972 1 Assistant Examiner-A. T. Grimley Appl.No.: 244,463

US. Cl ..174/16 R, 52/20, 94/37,

FOREIGN PATENTS OR APPLICATIONS Great Britain 174/37 Att0rneyRichard L.Gausewitz et a1.

[5 7] ABSTRACT The enclosure for buried transformers is formed of twoseparate fiberglass parts, namely a hole liner and a cover. The holeliner comprises two corresponding semicylindrical sections which arejoined together and then mounted around the transformer, in verticalrelationship. The cover comprises a top portion and a skirt portion, andincludes depending conduits for convecting cooling air down to thebottom of the hole liner. The convected air then passes upwardly througha central opening in the top portion of the cover. In accordance withthe method, earth is compacted around the hole liner, following whichthe cover is mounted in telescoped relationship around the upper regionof the hole liner. The cover is supported on the compacted earth, not onthe hole liner, which means that the cover position is readily adjustedin the event the grade changes.

24 Claims, 7 Drawing Figures PATENTED 1 73 SHEET 1 OF 2 PATENTEB APR 1 7I373 SHEET 2 [1F 2 BACKGROUND OF THE INVENTION 1. Field of the InventionThis invention relates to the field of of enclosures for undergroundutility equipment. More particularly, this invention relates to thefield of enclosures for buried transformers forming parts of electricalutility systems.

2. Description of Prior Art It is becoming increasingly common to layunderground the electric power lines leading to newlybuilt homes, etc.The transformers associated with such power lines are also placedunderground, and it is customary practice to house such undergroundtransformers in pre-cast concrete enclosures. These are very heavy andtherefore difficult to transport and place. Furthermore, such concreteenclosures are bulky and awkward to store prior to use.

The exposed cover portions of conventional concrete enclosures forunderground transformers rest on the hole-liner portions thereof.Therefore if the grade changes after the hole liner is placed inposition, it is very difficult to orient properly the exposed cover tothe new or changed grade. Another problem is that the heaviness ofconcrete hole liners causes them to sink and/or tip in the earth,particularly after protracted rains. When this occurs, the coverslikewise sink and/or tip, which is highly undesirable.

Underground transformers require that a means be provided to convect airfor cooling purposes. Conventionally, the convection inducing means isexpensive, and/or does not induce air flow at regions below the upperend of the transformer. Therefore, cooling of the transformers hasheretofore been inefficient and/or impractical.

SUMMARY OF THE INVENTION In accordance with one aspect of the presentinvention, the cover of an underground transformer enclosure is notmounted on the hole liner, but is instead telescoped over the hole linerand supported on and in the surrounding earth. The relationship iscaused to be such that the cover may be adjusted in position at'any timeand throughout a substantial range of adjustment, thereby facilitatingadaptation of the enclosure to changes in the grade.

In accordance with a second aspect of the invention, the transformer iscooled convectively by air which passes downwardly through conduitsdepended from the cover. The conduits pass to the bottom portion of theenclosure, so that the air flow is operative to cool the full length ofthe transformer.

The cover comprises a removable air-transmissive grid which covers notonly the upper ends of the conduits, but also a central opening in thecover. The cover and the hole liner are formed of light-weightfiberglass, instead of concrete. Furthermore, the hole liner is formedof corresponding halves which are readily manufactured, stored andshipped.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. 1 is an isometric view of a transformer enclosure constructed inaccordance with the present invention;

FIG. 2 is an enlarged exploded isometric view of the cover portion ofthe enclosure;

FIG. 3 is an enlarged vertical sectional view, taken on line 33 of FIG.1;

FIG. 4 is a horizontal section taken on line 4-4 of FIG. 3; and

FIGS. 5-7 are elevational views illustrating the method of installation.7

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, theenclosure for underground transformers is illustrated to comprise a holeliner l0 and a cover 11, each formed of glass fibers and syntheticbonding resin (for example, a polyester or epoxy). Hole liner 10comprises two identical semicylindrical sections 12 and 13 (FIGS. 1 and4) having outwardly-extending longitudinal flanges 14 at the side edgesthereof and outwardly-extending arcuate flanges 16 at the end edgesthereof.

Longitudinal flanges 14 are secured together by bolts 17, thus providinga continuous cylindrical hole liner having radially-outwardly extendingcircular flanges at the respective ends thereof. Such flanges formed byelements 16 are disposed in planes which are perpendicular to thelongitudinal axis of the liner.

As best shown in FIG. 3, a plurality of longitudinally spacedoutwardly-extending circular ribs or beads 18 are provided integrally onthe exterior of the hole liner, such ribs cooperating with the circularflanges in increasing the strength of the liner. The beads 18 are spacedapart sufficiently far to permit passage therebetween of the electricalconduit 19 which extends inwardly to the transformer, which isschematically represented at 21. It is pointed out that transformer 21is mounted in vertical relationship, coaxially of the liner l0 and inthe lower portion of the chamber defined within the liner.

Proceeding next to a description of the cover I 1, this is indicated asbeing a generally cylindrical element although it may be of variousother desired shapes, for example rectangular. Because the cover 11 isnot mounted on the hole liner 10, but instead is supported on and in theearth as described hereinafter, a rectangular cover (for example) isreadily employed even with a cylindrical hole liner 10.

The cover 11 has a skirt or side wall 22 which is (as above stated)generally cylindrical, being preferably slightly frustoconical in orderto facilitate release from the mold in which it is made, and also topermit nesting when desired. The inner diameter of the skirt 22 isslightly larger (FIG. 3) than the outer diameter of the flange 16 at theupper end of the hole liner. The construction is therefore such thatcover 11 may be disposed in various positions relative to the upper endof the hole liner, in telescoped relationship, the degree of telescopingbeing determined by factors described below.

At the lower edge of the side wall 22 is a radially-outwardly extendingflange 23 which is disposed in a plane perpendicular to the axis of thecover, and which serves as a foot or bearing means to prevent undesireddownward movement of the cover into the earth. Flange 23 also serves,when covered with earth or other fill material, as an anchor meanspreventing undesired upward movement of the cover.

The upper wall 24 of cover 11 is horizontal, being perpendicular to theaxis of the cover and of the hole liner l0, and is integral with theskirt or side wall 22. As best shown in FIGS. 2 and 3, upper wall 24 hasa square depressed portion 26 which is sufficiently depressed (indentedbelow the upper surface of the surrounding portion of wall 24) that asquare metal grid 27 may be mounted therein in substantially flushrelationship to the upper surface of wall 24. Grid 27 is adapted to besecured to the remainder of the cover, by suitable screws (not shown).

The depressed portion 26 of wall 24 is partially cut out in order toform a large octagonal opening 28 (FIG. 2). Opening 28 is defined byfour relatively long hypotenuse edges 29 which are so oriented that theyform respectively, four right triangles T in the corner regions of thedepressed portion 26. The remaining four edges 31 of the octagonalopening 28 are respectively parallel to and faced inwardly of thecentral regions of the sides of depressed portion 26, so that ledges Lare formed.

First and second hanger supports 32 are disposed at right angles to eachother across the opening 28 (FIG. 2), the protruding ends of the hangersupports being seated on the ledges L. Hangers 33 extend downwardly fromthe hanger supports 32 and support in horizontal relationship arectangular louver assembly 34.

Louver 34 permits upward circulation of air from transformer 21 andthrough the opening 28 and grid 27 thereon. However, the louvercooperates with the grid in preventing downward passage of undesiredobjects to the vicinity of the transformer 21. For example, the louverassembly 34 prevents children from introducing wires, which could createa shock hazard, into the hole liner. v

There will next be described the means for convecting cooling air to thebottom region of hole liner 10, in the space surrounding the transformer21, so that a very efficient flow of cooling air is created over thetransformer and up through the louver assembly 34 and the opening 28.Such cooling means comprises a plurality of elongated conduits 36 whichare mounted in dependent relationship from the cover wall 24, and whichextend into the annulus between transformer 21 and the lower portion ofhole liner 10. The conduits 36 are preferably formed of plastic, orother electrical nonconductor, in order that there will be no shockhazard.

Eight such conduits 36 are illustrated, there being two mounted independent relationship from each triangular corner T of depressedportion 26. Mounting of the conduits is readily effected by providingradiallyoutwardly extending flanges at the upper ends thereof, whichflanges seat in corresponding counterbores in corners T. The shank orbody portions of the conduits extend downwardly through openings in thecorners T. The lower ends of the conduits are preferably cut off in abeveled or inclined manner, as illustrated, in order to prevent themfrom being caught on the transformer 21 or on cable 19 during mountingofthe cover.

It is pointed out that the upper ends of conduits 36 are covered by thegrid 27, as is the opening 28. Thus, all portions of the convectivecirculation means are covered by the grid 27. Because the grid 27 issecured by screws to the remainder of the cover, the tubes are held inposition (against upward movement) without the necessity of beingadhesively secured to the cover.

DESCRIPTION OF THE METHOD The first step in the method comprisesexcavating a hole which is substantially deeper than the length of holeliner 11), and which has a diameter substantially greater than that ofthe hole liner. Such hole is indicated at 41 in FIGS. 5-7. A layer ofgravel 42 is placed at the bottom of the hole 41, to serve as a supportfor the transformer 21 and the hole liner 10, and to aid in the drainageof water which enters through opening 28. The gravel layer is madesufficiently thin that the upper end ofliner 10 is spaced below gradelevel.

The liner 10 is then mounted in hole 41 in vertical relationship, thispreferably occurring after the electrical conduit 19 (FIG. 3) is passedthrough the wall of the liner. Transformer 21 is mounted coaxially atthe bottom of the liner 111, in supported relationship on gravel 42, andis connected to conduit 19. FIG. 5 illustrates the condition of theparts at this stage of the operation (the transformer 21 and its conduit19 being in position as shown in FIG. 3).

Referring next to FIG. 6, the next step in the method comprisesbackfllling earth 43 into the annulus or space which surrounds liner 10.Such earth is tamped and thus compacted in order to reduce settling to aminimum. The horizontal surface 44 of the backfllled earth 43 is causedto be spaced a substantial distance (defined below) below the flange 16at the upper end of liner 10.

The next step in the method comprises mounting the cover 11 intelescoped relationship over the upper end of the liner, so that theflange or bearing element 23 at the lower edge of the cover is supportedon upper surface 44 of earth 43. Such mounting of the cover 11automatically effects introduction of conduits 36 into the lower portionof the liner 10, radially-outwardly from transformer 21.

The depth of the hole 41, and the thickness of the layer of gravel 42,are correlated to the length of liner 10 and also to the verticaldimension of cover skirt 22 in such manner that the upper wall 24 of thecover will be at the desired elevation (at or above grade level) whenflange 23 and earth surface 44 are spaced a predetermined desireddistance beneath upper flange 16 of the liner. Such predetermineddesired distance is correlated to the grade level 46 (FIGS. 5-7), insuch manner that subsequent changes in the elevation of the cover may bemade in either direction both upwardly and downwardly.

Flange 23 is thus initially spaced sufficiently below upper flange 16that the cover may subsequently be raised substantially (to compensatefor grade elevation) without causing flange 23 to be above flange 16(which would make it possible for earth to pass into the hole liner). Onthe other hand, the degree of initial spacing of flange 23 below upperflange 16 is not sufficiently great that wall 24 is seated on or islocated near the flange 16. Therefore, it is possible to effectsubstantial lowering of the cover when the grade lowers.

If the grade 46 becomes lower, so that it is desired to lower the cover,it is merely necessary to remove the cover, remove some of the earth 43beneath the cover (thus lowering the upper surface 44 of the earth 43),and then replace the cover. Should the grade 46 become higher, theabove-indicated procedure is followed except that earth is added to theearth 43 to thereby raise the upper surface 44. The cover 11 restssolely and directly on the earth, not on liner 10, at all times exceptin response to a rare occasion when the grade level becomes very muchlower than it was when the enclosure was buried. The word earth, asemployed in the accompanying claims, denotes any desired fill material.

It is emphasized that, since the cover rests upon earth and not upon thehole liner 10, any tilting of the hole liner (for example, caused bysoaking of water into the earth) will not affect the cover. Should anytilting of the cover occur, it is readily corrected in the mannerindicated above, and without the necessity of touching the hole liner10. It is noted, however, that because of the light-weight constructionof both the hole liner and the cover, settling and tilting of thevarious are maintained at a minimum.

As the final step in the method, additional earth (or other desired fillmaterial) 47 is backfilled and compacted above the flange 23. The degreeof filling is preferably such that the upper surface of the additionalearth 47 is flush with grade 46. Because flange 23 serves as an anchor,the additional earth 47 holds the cover in position, However, the coveris readily removable if and when it is desiredtochange the elevation orinclination of the cover as described above.

Access may be had to transformer 21 without the necessity of removingthe entire cover, this being effected by merely removing the grid 27 andthen lifting on the hanger supports 32 to cause the louver element 34 topass upwardly through opening 28.

It is to be understood that the various elements 11, 36, 33, 34, etc.,may be preassembled a the factory. Alternatively, the covers 11 may bemounted in nested relationship, and the assembly thereof with elements36, etc., may be readily effected at the job site. Similarly, thevarious halves 12 and 13 of the cylindrical hole liner may be readilyassembled at the job site by means ofthe bolts 17 (FIGS. 1 and 4).

Although the invention has been described in connection withtransformers, certain aspects of the invention are also applicable togas meters, electric meters, valves, and other types of utilityequipment which may be located underground.

The foregoing detailed description is to be clearly understood as givenby way of illustration and example only, the spirit and scope of thisinvention being limited solely by the appended claims.

I claim:

1. An enclosure for underground utility equipment, which comprises:

a. a hole liner disposed in the ground,

said hole liner having an open upper end,

said hole liner enclosing utility equipment, and

b. a cover having an upper wall and having a depending skirt whichextends downwardly from said upper wall,

the inner diameter of said skirt being greater than the outer diameterof said upper end of said hole liner,

said skirt being telescoped downwardly around said upper end of saidhole liner to prevent entrance of earth into said hole liner,

said upper wall of said cover being spaced above said upper end of saidhole liner,

components said skirt and thus said cover being supported by the earthat regions around said upper end of said hole liner, the support of saidskirt and of said cover being independent of said hole liner.

2. The invention as claimed in claim 1, in which said upper wall of saidcover is at or above grade level and has an opening therethrough, and inwhich a protective element is removably mounted over said opening, saidprotective element being removable without moving said skirt.

3. The invention as claimed in claim 1, in which said skirt has anoutwardly-extending flange at the lower portion thereof, said flangeresting on the earth to provide support for said cover, said flangebeing buried and thus serving as an anchor.

4. The invention as claimed in claim 1, in which both said cover andsaid hole liner are formed of fiberglass and synthetic bonding resin.

5. The invention as claimed in claim 4, in which said hole liner iscylindrical and has radially-outwardly extending flanges at the upperand lower ends thereof, in which said hole liner is formed of twosemicylindrical sections each having outwardly-extending flanges at eachside edge thereof, and in which means are provided to secure saidlast-mentioned flanges to each other.

6. The invention as claimed in claim 1, in which said utility equipmentis an underground transformer, in which said upper wall of said coverhas an opening therethrough, and in which a protective element isremovably mounted over said opening, said protective element beingremovable without moving said skirt, said protective element beingadapted to permit passage of air therethrough for cooling of saidtransformer.

7. An enclosure for underground transformers, which comprises:

a. a hole liner adapted to be buried in the ground in verticalrelationship,

said hole liner having an open upper end,

said hole liner being adapted to have an electrical utility transformermounted therein,

b. an exposed cover having an upper wall adapted to be positionedoversaid upper end of said hole liner to prevent entrance of earth and ofundesired objects into said hole liner, said upper wall of said coverbeing spaced above said upper end of said hole liner and said coverhaving opening means therethrough adapted to permit upward convection ofcooling air from said transformer to the ambient atmosphere, and

c. conduit means adapted to be mounted in dependent relationship on saidcover and to extend downwardly therefrom to hole liner,

said conduit means permitting downward convec tion of cooling airtherethrough from the ambient atmosphere and to the vicinity of saidtransformer,

said air then convecting upwardly and passing outwardly through openingmeans in said cover.

the space within said i 8. The invention as claimed in claim 7, in whichsaid conduit means comprise a substantial number of tubes mounted independent relationship from said cover, and extending downwardly to thelower end of said hole liner.

9. The invention as claimed in claim 8, in which an air-transmissiveelement is mounted over said cover, said element covering both saidopening means and the upper ends of said tubes.

10. The invention as claimed in claim 9, in which said cover is formedof fiberglass and synthetic bonding resin, in which said opening meanscomprises an opening through the central region of said cover, in whichportions of said cover around said opening are recessed downwardly inorder to seat said air-transmissive element, and in which said tubesextend through said depressed portions of said cover and on oppositeside portions of said opening.

11. The invention as claimed in claim 7, in which a protective elementis mounted in dependent relationv ship from said cover and generallyparallel to said cover, said protective element being spaced beneathsaid opening means in said cover.

12. The invention as claimed in claim 7, in which said conduit meanscomprises a substantial number of electrically nonconductive tubesmounted in dependent relationship from said cover, in which anair-transmissive grid is mounted over said cover and covers both saidopening means and the upper ends of said tubes, in which said cover isformed of fiberglass and synthetic bonding resin, in which said openingmeans comprises a large opening through the central region of saidcover, in which portions of said cover around said large opening arerecessed downwardly in order to seat said grid, and in which said tubesextend through said recessed portions of said cover and on opposite sideportions of said large opening.

13. The invention as claimed in claim 12, in which an air-transmissiveprotective element is mounted in dependent relationship from said coverand generally parallel thereto, said protective element being spaced asubstantial distance beneath said large opening in said cover, saidprotective element being supported by hangers which, in turn, aresuspended from hanger supports bridged across said large opening.

14. An enclosure for underground transformers,

which comprises:

a. a hole liner buried in the ground in vertical relationship, said holeliner having an open upper end which is below grade level, said holeliner having an electrical utility transformer mounted therein, b. acover having an upper wall and having a depending skirt which extendsdownwardly from said upper wall, the inner diameter of said skirt beinggreater than the outer diameter of said upper end of said hole liner,

said skirt being telescoped downwardly around said upper end of saidhole liner to prevent entrance of earth into said hole liner,

said upper wall of said cover being spaced above said upper end of saidhole liner,

said skirt and thus said cover being supported by the earth at regionsaround said upper end of said hole liner, the support of said skirt andof said cover being independent of said hole liner, said upper wall ofsaid cover being at or above grade level and being exposed to view, and

c. means to effect convective circulation of air from the ambientatmosphere down to the lower regions of said hole liner around saidtransformer to thereby effect cooling of said transformer, saidcirculation means comprising an opening in said cover adapted to permitupward convection of air from the vicinity of said transformer,

said circulation means further comprising a plurality of conduitsmounted in dependent relationship from said cover,

the upper ends of said conduits communicating with the ambientatmosphere,

the lower ends of said conduits communicating with said hole liner atregions spaced around the lower end of said transformer.

15. The invention as claimed in claim 14, in which said cover and saidhole liner are formed of fiberglass and synthetic bonding resin.

16. An enclosure for underground utility equipment, which comprises:

a. a vertical hole liner formed of fiberglass and synthetic bondingresin, and having an open upper end, said hole liner being buried in theearth and with said upper end spaced below grade level,

b. a cover formed of fiberglass and synthetic bonding resin, and havingan upper wall and a depending skirt the inner diameter of which isgreater than the outer diameter of said upper end of said hole liner,said skirt being telescoped downwardly over said upper end of said holeliner and with said upper wall of said cover spaced above said upper endof said hole liner,

said skirt having an outwardly-extending flange at the lower end thereofand seated on the earth around said hole liner,

said outwardly-extending flange on said skirt forming the sole supportfor said cover whereby said cover is supported independently of saidhole liner and may be adjusted independently thereof, and

c. a mass of material mounted around said skirt and above said flange atthe lower end thereof and serving as a weight and support to maintainsaid cover against upward shifting, said mass of material beingremovable in order to permit shifting of said cover when desired inorder to compensate for factors including change of grade.

17. The invention as claimed in claim 16, in which an electrical utilitytransformer is mounted in said hole liner, and in which means areprovided to effect convective circulation of air through said cover anddown into said hole liner to thereby air in cooling said transfonner.

18. The invention as claimed in claim 17, in which said convectivecirculation means includes a large opening in the central region of saidupper wall of said cover, and further includes a substantial number ofvertical tubes extending through said upper wall of cover and downwardlyinto the lower portion of said hole liner in spaced relationship aroundthe lower end of said transformer, said tubes permitting downwardconvection of air to the lower end of said hole liner and said centralopening permitting upward convection of air from said hole liner.

19. The invention as claimed in claim 18, in which a protective louveris mounted in said cover in spaced relationship below said upper wallthereof, and in which a grid is removably secured to said upper wall ofsaid cover over said opening therethrough and over the upper ends ofsaid tubes.

20. The invention as claimed in claim 16, in which said hole liner isformed of two semicylindrical sections secured to each other, and inwhich said hole liner has outwardly-extending flanges at the upper andlower ends thereof.

21. A method of providing an enclosure for an underground utilityservice element, which comprises:

a. providing a hole liner adapted to be mounted in the earth in verticalrelationship,

b. excavating a hole in the earth having a depth substantially greaterthan the vertical dimension of said hole liner, and having a diameterlarger than the diameter of said hole liner, I

c. mounting said hole liner in said hole in vertical relationship andwith the upper end of said hole liner spaced below the level of thegrade around said hole,

d. backfilling earth into said hole around said hole liner and to such adepth that the upper surface of the backfilled earth is spaced below theupper end of said hole liner,

e. providing a cover element having an upper wall and having a dependingskirt the inner diameter of which is larger than the diameter of theupper end of said hole liner,

f. mounting said cover over said hole liner in telescoped relationshipand with the lower portion of said skirt seated on the upper portion ofthe backfilled earth,

g. correlating the elevation of the upper surface of said backfilledearth with the vertical dimension of said skirt and with the distancethat the upper end of said hole liner is spaced below grade level, insuch manner that said upper wall of said cover is spaced above saidupper end of said hole liner and is flush with or somewhat above gradelevel, and

h. backfilling material around said skirt and up to grade level wherebyto maintain said cover in position and provide a decorative end product,whereby said cover may subsequently be raised or lowered to compensatefor changes in grade level, by removing said cover and changing thelevel of the upper end of said backfilled earth.

22. The invention as claimed in claim 21, in which said method furthercomprises employing a cover having an outwardly-extending flange at thelower region of said skirt, and effecting said backfilling of saidlastmentioned material above said flange.

23. The invention as claimed in claim 21, in which said method furthercomprises emplp ing a hole liner avmg an open lower en and provi mggravel at the bottom of said hole in order to adjust the verticalposition of said hole liner and in order to aid in effecting drainage ofwater from said hole liner.

24. A method of providing an enclosure for an underground utilityservice element, which comprises:

a. providing a hole liner adapted to be mounted in the earth in verticalrelationship, b. excavating a hole in the earth having a diameter largerthan the diameter of said hole liner, 0. mounting said hole liner insaid hole in vertical relationship,

backfilling earth into said hole around said hole liner and to such adepth that the upper surface of the backfilled earth is spaced below theupper end of said hole liner,

e. providing a cover element having an upper wall and having a dependingskirt the inner diameter of which is larger than the diameter of theupper end of said hole liner,

f. mounting said cover over said hole liner in telescoped relationshipand with the lower portion of said skirt seated on the upper portion ofthe backfilled earth,

g. correlating the elevation of the upper surface of said backfilledearth with the vertical dimension of said skirt in such manner that saidupper wall of said cover is flush with or somewhat above grade level,and

h. backfilling material around said skirt whereby to maintain said coverin position and provide a decorative end product, whereby said cover maysubsequently be adjusted to compensate for changes in grade level, byremoving said cover and changing the level of the upper end of saidbackfilled earth.

1. An enclosure for underground utility equipment, which comprises: a. ahole liner disposed in the ground, said hole liner having an open upperend, said hole liner enclosing utility equipment, and b. a cover havingan upper wall and having a depending skirt which extends downwardly fromsaid upper wall, the inner diameter of said skirt being greater than theouter diameter of said upper end of said hole liner, said skirt beingtelescoped downwardly around said upper end of said hole liner toprevent entrance of earth into said hole liner, said upper wall of saidcover being spaced above said upper end of said hole liner, said skirtand thus said cover being supported by the earth at regions around saidupper end of said hole liner, the support of said skirt and of saidcover being independent of said hole liner.
 2. The invention as claimedin claim 1, in which said upper wall of said cover is at or above gradelevel and has an opening therethrough, and in which a protective elementis removably mounted over said opening, said protective element beingremovable without moving said skirt.
 3. The invention as claimed inclaim 1, in which said skirt has an outwardly-extending flange at thelower portion thereof, said flange resting on the earth to providesupport for said cover, said flange being buried and thus serving as ananchor.
 4. The invention as claimed in claim 1, in which both said coverand said hole liner are formed of fiberglass and synthetic bondingresin.
 5. The invention as claimed in claim 4, in which said hole lineris cylindrical and has radially-outwardly extending flanges at the upperand lower ends thereof, in which said hole liner is formed of twosemicylindrical sections each having outwardly-extending flanges at eachside edge thereof, and in which means are provided to secure saidlast-mentioned flanges to each other.
 6. The invention as claimed inclaim 1, in which said utility equipment is an underground transformer,in which said upper wall of said cover has an opening therethrough, andin which a protective element is removably mounted over said opening,said protective element being removable without moving said skirt, saidprotective element being adapted to permit passage of air therethroughfor cooling of said transformer.
 7. An enclosure for undergroundtransformers, which comprises: a. a hole liner adapted to be buried inthe ground in vertical relationship, said hole liner having an openupper end, said hole liner being adapted to have an electrical utilitytransformer mounted therein, b. an exposed cover having an upper walladapted to be posItioned over said upper end of said hole liner toprevent entrance of earth and of undesired objects into said hole liner,said upper wall of said cover being spaced above said upper end of saidhole liner and said cover having opening means therethrough adapted topermit upward convection of cooling air from said transformer to theambient atmosphere, and c. conduit means adapted to be mounted independent relationship on said cover and to extend downwardly therefromto the space within said hole liner, said conduit means permittingdownward convection of cooling air therethrough from the ambientatmosphere and to the vicinity of said transformer, said air thenconvecting upwardly and passing outwardly through opening means in saidcover.
 8. The invention as claimed in claim 7, in which said conduitmeans comprise a substantial number of tubes mounted in dependentrelationship from said cover, and extending downwardly to the lower endof said hole liner.
 9. The invention as claimed in claim 8, in which anair-transmissive element is mounted over said cover, said elementcovering both said opening means and the upper ends of said tubes. 10.The invention as claimed in claim 9, in which said cover is formed offiberglass and synthetic bonding resin, in which said opening meanscomprises an opening through the central region of said cover, in whichportions of said cover around said opening are recessed downwardly inorder to seat said air-transmissive element, and in which said tubesextend through said depressed portions of said cover and on oppositeside portions of said opening.
 11. The invention as claimed in claim 7,in which a protective element is mounted in dependent relationship fromsaid cover and generally parallel to said cover, said protective elementbeing spaced beneath said opening means in said cover.
 12. The inventionas claimed in claim 7, in which said conduit means comprises asubstantial number of electrically nonconductive tubes mounted independent relationship from said cover, in which an air-transmissivegrid is mounted over said cover and covers both said opening means andthe upper ends of said tubes, in which said cover is formed offiberglass and synthetic bonding resin, in which said opening meanscomprises a large opening through the central region of said cover, inwhich portions of said cover around said large opening are recesseddownwardly in order to seat said grid, and in which said tubes extendthrough said recessed portions of said cover and on opposite sideportions of said large opening.
 13. The invention as claimed in claim12, in which an air-transmissive protective element is mounted independent relationship from said cover and generally parallel thereto,said protective element being spaced a substantial distance beneath saidlarge opening in said cover, said protective element being supported byhangers which, in turn, are suspended from hanger supports bridgedacross said large opening.
 14. An enclosure for undergroundtransformers, which comprises: a. a hole liner buried in the ground invertical relationship, said hole liner having an open upper end which isbelow grade level, said hole liner having an electrical utilitytransformer mounted therein, b. a cover having an upper wall and havinga depending skirt which extends downwardly from said upper wall, theinner diameter of said skirt being greater than the outer diameter ofsaid upper end of said hole liner, said skirt being telescopeddownwardly around said upper end of said hole liner to prevent entranceof earth into said hole liner, said upper wall of said cover beingspaced above said upper end of said hole liner, said skirt and thus saidcover being supported by the earth at regions around said upper end ofsaid hole liner, the support of said skirt and of said cover beingindependent of said hole liner, said upper wall of said cover being ator above grade level and being exposed To view, and c. means to effectconvective circulation of air from the ambient atmosphere down to thelower regions of said hole liner around said transformer to therebyeffect cooling of said transformer, said circulation means comprising anopening in said cover adapted to permit upward convection of air fromthe vicinity of said transformer, said circulation means furthercomprising a plurality of conduits mounted in dependent relationshipfrom said cover, the upper ends of said conduits communicating with theambient atmosphere, the lower ends of said conduits communicating withsaid hole liner at regions spaced around the lower end of saidtransformer.
 15. The invention as claimed in claim 14, in which saidcover and said hole liner are formed of fiberglass and synthetic bondingresin.
 16. An enclosure for underground utility equipment, whichcomprises: a. a vertical hole liner formed of fiberglass and syntheticbonding resin, and having an open upper end, said hole liner beingburied in the earth and with said upper end spaced below grade level, b.a cover formed of fiberglass and synthetic bonding resin, and having anupper wall and a depending skirt the inner diameter of which is greaterthan the outer diameter of said upper end of said hole liner, said skirtbeing telescoped downwardly over said upper end of said hole liner andwith said upper wall of said cover spaced above said upper end of saidhole liner, said skirt having an outwardly-extending flange at the lowerend thereof and seated on the earth around said hole liner, saidoutwardly-extending flange on said skirt forming the sole support forsaid cover whereby said cover is supported independently of said holeliner and may be adjusted independently thereof, and c. a mass ofmaterial mounted around said skirt and above said flange at the lowerend thereof and serving as a weight and support to maintain said coveragainst upward shifting, said mass of material being removable in orderto permit shifting of said cover when desired in order to compensate forfactors including change of grade.
 17. The invention as claimed in claim16, in which an electrical utility transformer is mounted in said holeliner, and in which means are provided to effect convective circulationof air through said cover and down into said hole liner to thereby airin cooling said transformer.
 18. The invention as claimed in claim 17,in which said convective circulation means includes a large opening inthe central region of said upper wall of said cover, and furtherincludes a substantial number of vertical tubes extending through saidupper wall of cover and downwardly into the lower portion of said holeliner in spaced relationship around the lower end of said transformer,said tubes permitting downward convection of air to the lower end ofsaid hole liner and said central opening permitting upward convection ofair from said hole liner.
 19. The invention as claimed in claim 18, inwhich a protective louver is mounted in said cover in spacedrelationship below said upper wall thereof, and in which a grid isremovably secured to said upper wall of said cover over said openingtherethrough and over the upper ends of said tubes.
 20. The invention asclaimed in claim 16, in which said hole liner is formed of twosemicylindrical sections secured to each other, and in which said holeliner has outwardly-extending flanges at the upper and lower endsthereof.
 21. A method of providing an enclosure for an undergroundutility service element, which comprises: a. providing a hole lineradapted to be mounted in the earth in vertical relationship, b.excavating a hole in the earth having a depth substantially greater thanthe vertical dimension of said hole liner, and having a diameter largerthan the diameter of said hole liner, c. mounting said hole liner insaid hole in vertical relationship and with the upper end of said holeLiner spaced below the level of the grade around said hole, d.backfilling earth into said hole around said hole liner and to such adepth that the upper surface of the backfilled earth is spaced below theupper end of said hole liner, e. providing a cover element having anupper wall and having a depending skirt the inner diameter of which islarger than the diameter of the upper end of said hole liner, f.mounting said cover over said hole liner in telescoped relationship andwith the lower portion of said skirt seated on the upper portion of thebackfilled earth, g. correlating the elevation of the upper surface ofsaid backfilled earth with the vertical dimension of said skirt and withthe distance that the upper end of said hole liner is spaced below gradelevel, in such manner that said upper wall of said cover is spaced abovesaid upper end of said hole liner and is flush with or somewhat abovegrade level, and h. backfilling material around said skirt and up tograde level whereby to maintain said cover in position and provide adecorative end product, whereby said cover may subsequently be raised orlowered to compensate for changes in grade level, by removing said coverand changing the level of the upper end of said backfilled earth. 22.The invention as claimed in claim 21, in which said method furthercomprises employing a cover having an outwardly-extending flange at thelower region of said skirt, and effecting said backfilling of saidlast-mentioned material above said flange.
 23. The invention as claimedin claim 21, in which said method further comprises employing a holeliner having an open lower end, and providing gravel at the bottom ofsaid hole in order to adjust the vertical position of said hole linerand in order to aid in effecting drainage of water from said hole liner.24. A method of providing an enclosure for an underground utilityservice element, which comprises: a. providing a hole liner adapted tobe mounted in the earth in vertical relationship, b. excavating a holein the earth having a diameter larger than the diameter of said holeliner, c. mounting said hole liner in said hole in verticalrelationship, d. backfilling earth into said hole around said hole linerand to such a depth that the upper surface of the backfilled earth isspaced below the upper end of said hole liner, e. providing a coverelement having an upper wall and having a depending skirt the innerdiameter of which is larger than the diameter of the upper end of saidhole liner, f. mounting said cover over said hole liner in telescopedrelationship and with the lower portion of said skirt seated on theupper portion of the backfilled earth, g. correlating the elevation ofthe upper surface of said backfilled earth with the vertical dimensionof said skirt in such manner that said upper wall of said cover is flushwith or somewhat above grade level, and h. backfilling material aroundsaid skirt whereby to maintain said cover in position and provide adecorative end product, whereby said cover may subsequently be adjustedto compensate for changes in grade level, by removing said cover andchanging the level of the upper end of said backfilled earth.